1. Technical Field of the Invention
The present invention relates to novel topically applicable cosmetic and/or dermatological compositions well suited for the photoprotection of the skin and/or hair against the deleterious effects of ultraviolet radiation (such compositions hereinafter more simply referred to as "sunscreen" or "antisun" compositions).
This invention more especially relates to sunscreen compositions comprising, in a cosmetically acceptable support (vehicle, diluent or carrier), a combination of a first specific screening agent, namely, a specific sulfonic derivative of benzimidazole, and at least one second specific screening agent judiciously selected from among the benzotriazole silicones.
2. Description of the Prior Art
It is known to this art that light radiation of wavelengths of from 280 nm to 400 nm promotes tanning of the human epidermis, and that light irradiation of wavelengths more particularly ranging from 280 to 320 nm, i.e., UV-B irradiation, causes skin burns and erythema which may be harmful to the development of a natural tan. For these reasons, as well as for aesthetic reasons, there is a constant demand for controlling this natural tanning in order, thus, to control the coloration of the skin; this UV-B radiation must thus be screened from the skin.
It is also known to this art that UV-A radiation, of wavelengths of from 320 to 400 nm, which tans the skin, also adversely affects it, especially in the case of sensitive skin or of skin which is continually exposed to solar radiation. TV-A rays cause, in particular, a loss of elasticity of the skin and the appearance of wrinkles, promoting premature skin aging. Such irradiation promotes triggering of the erythemal reaction or amplifies this reaction in certain individuals and may even be the source of phototoxic or photoallergic reactions. Thus, for aesthetic and cosmetic reasons such as conservation of the natural elasticity of the skin, for example, an ever-increasing number of individuals seek to control the effects of UV-A radiation on their skin. It is thus desirable to also screen UW-A radiation from the skin and/or hair.
A very wide variety of cosmetic compositions intended for the photoprotection (UV-A and/or UV-B) of the skin are known to this art.
These photoprotective compositions are typically oil-in-water emulsions (namely, a cosmetically acceptable vehicle, diluent or carrier comprising a continuous aqueous dispersing phase and a discontinuous oily dispersed phase) which contain, in various concentrations, one or more conventional lipophilic and/or hydrophilic organic screening agents capable of selectively absorbing harmful UV radiation. These screening agents (and the amounts thereof) are selected as a function of the desired sun protection factor (SPF) which is expressed mathematically by the ratio of the irradiation time required to reach the erythema-forming threshold with the UV screening agent, to the time required to reach the erythema-forming threshold without UV screening agent.